JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
  <div class="flexbox">
  <div class="flexbox__section">
    <div class="item">1</div>
    <div class="item">2</div>
    <div class="item">3</div>
    <div class="item">4</div>
    <div class="item">5</div>
  </div>
  <div class="flexbox__section">
    <div class="item">6</div>
    <div class="item">7</div>
    <div class="item">3</div>
  </div>
  <div class="flexbox__section">
    <div class="item">8</div>
  </div>
</div>
</div>

SCSS

$blue: #0084ff;

body {
  background: white;
  font-family: Helvetica;
}
.wrapper {
  height: 300px;
  overflow-y: auto;
  border: 1px dotted red;
}
.flexbox {
  //display: flex;
  //justify-content: flex-start;
  ///align-items: center;
  //flex-direction: column;
  //flex-wrap: wrap;
  width: 100%;
  //height: 300px;
  padding: 25px 0;
  //overflow-y: auto;
  //overflow-x: hidden;
  columns: 2 auto; //или columns: 2 320px; как удобнее

  &__section {
    //flex-shrink: 0;
    display: inline-block;
    width: 320px;
    border-bottom: 1px solid rgba($blue, 50%);
    padding-bottom: 24px;
    margin-bottom: 24px;

    &:last-child {
      border-bottom: none;
      padding-bottom: 0;
      margin-bottom: 0;
    }
  }
}

.item {
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: $blue;
  border-radius: 3px;
  padding: 20px 0;
  margin-bottom: 16px;

  &:last-child {
    margin-bottom: 0;
  }
}